250 THE BLOOD. 



This substance is called fibrin-globulin by HAMMARSTEN. The recent 

 investigations of HUISKAMP have shown that this substance is not formed 

 as a cleavage product from pure fibrinogen, but occurs in plasma or in 

 fibrinogen solutions not purified of sodium fluoride besides the fibrinogen, 

 or perhaps in loose combination with fibrinogen. The view that a cleavage 

 takes place in the coagulation of the fibrinogen has not been supported 

 by these investigations. 1 



Opinions are not unanimous in regard to the enzyme nature of throm- 

 bin and the enzymotic formation of fibrin, and there are, indeed, investiga- 

 tors who consider the coagulation as a physical process or a reaction 

 between colloids (IscovEsco, NOLF and others 2 ). A more thorough 

 discussion of this subject can take place only in connection with the 

 coagulation of the blood. 



Nucleoprotein. This substance, which, as above-mentioned, is considered 

 by PEKELHARING and HUISKAMP as identical with the prothrombin or thrombin, 

 occurs in the blood-plasma as well as in the serum, and is precipitated from the 

 latter with the globulin. It is similar to the globulin in that it is readily soluble 

 in neutral salt solution, and can be completely salted out on saturation with 

 magnesium sulphate, and separates only incompletely on dialysis. It is much 

 less soluble than serglobulin in an excess of dilute acetic acid, and coagulates 

 at 65-69 C. C. G. LIEBERMEISTER 3 found only 0.08-0.09 per cent phosphorus 

 in the nucleoprotein, which indicates that the nucleoprotein was contaminated with 

 other proteins. He also found that the substance was soluble in acetic acid with 

 difficulty, a property which is used by PEKELHARING as an important means of 

 separating the compound proteins from the globulins. 



Serglobulins, also called paraglobulin (KUHNE), fibrinoplastic substance 

 (ALEX. SCHMIDT), serum-casein (PANUM 4 ), occur in the plasma, serum, 

 lymph, transudates and exudates, in the white and red corpuscles, and 

 probably in many animal tissues and form-elements, though in small 

 quantities. They are also found in the urine in many diseases. 



The so-called serglobulin is without doubt not an individual substance, 

 but consists of a mixture of two or more protein bodies which cannot be 

 completely and positively separated from each other. The mixture of 

 globulins obtained from blood-plasma or blood-serum by saturation 

 with magnesium sulphate or half-saturation with ammonium sulphate 

 consists of nucleoprotein, fibrin-globulin, and the true serglobulin or 

 mixture of globulins. 5 



1 See Hammarsten, Zeitschr. f. physiol. Chem., 28; Heubner, Arch. f. exp. Path. 

 u. Pharm., 49, and Zeitschr. f. physiol. Chem., 45; Huiskamp, ibid., 44 and 46. 



2 Iscovesco, Compt. rend. soc. biol., 60 and 61; Nolf, Arch, internat. d. Physiol., 

 6 (1908). 



3 Hofmeister's Beitrage, 8; Pekelharing and Huiskamp, 1. c. footnote 3, page 248. 

 4 Kiihne, Lehrbuch d. physiol. Chem., Leipzig, 1866-68; Alex. Schmidt, Arch. f. 



(Anat. u.) Physiol., 1861-62; Panum, Virchow's Arch., 3 and 4. 



5 Mellanby, Journ. of Physiol., 36, claims that no separation of the two chief 



